JP5203740B2 - Surface grinding head system for substrates - Google Patents

Description

  The present invention relates to a surface grinding head system for a substrate in which a cup wheel type grinding wheel is supported by a flange at the tip of a rotatable / linearly movable grinding wheel shaft supported by a hydrostatic bearing. This surface grinding head system is used for surface grinding of workpieces such as silicon bare wafers, semiconductor substrates, ceramic substrates, GaAs plates, sapphire substrates, etc., improving the planarization of the workpieces and increasing the grinding speed of the substrates. Is.

  After placing a workpiece such as a silicon bare wafer or semiconductor substrate on a porous ceramic rotary chuck table, rotate the grindstone shaft that supports the cupwheel grindstone and lower it to place the cupwheel grindstone on the workpiece surface. A surface grinding apparatus for grinding the surface of a workpiece by rubbing to reduce the thickness of the workpiece has been put into practical use. The reason for changing the inclination of the grindstone axis is to prevent grinding burn of the workpiece to be ground and to make the thickness distribution of the workpiece as uniform as possible.

  For example, grinding is performed by placing a wafer on a porous ceramic rotary chuck table that is rotationally driven in a horizontal plane, and grinding the wafer with a cup wheel type diamond grindstone attached to a lower portion of a grinding spindle head arranged in a vertical direction. In the apparatus, driving means for relatively moving the grinding spindle head and the wafer in the vertical z-axis direction, tilting means for rotating the grinding spindle head or wafer about the x-axis and the y-axis in a horizontal plane, Surface grinding with control means for controlling the driving means and the tilting means to change the feed amount of the grinding spindle head and the relative tilt between the grinding spindle head and the workpiece stepwise or continuously according to the stage of grinding A device has been proposed. The tilting means is provided in a column that fixes the lifting means of the grinding spindle head (see, for example, Patent Document 1).

In addition, a porous ceramic rotary chuck table for holding a workpiece, a grinding head that rotates by attaching a grindstone to a spindle, a bearing that supports the grindstone spindle, a magnetic bearing that controls tilting of the grinding head, and the grinding A sensor for detecting a relative attitude of the spindle with respect to the workpiece; and attitude control means for controlling the magnetic bearing so that the grinding wheel spindle assumes a preset attitude using detection data detected by the sensor. Using surface grinding, the workpiece and grinding wheel are moved relative to each other while the grinding wheel of the grinding head is pressed against the workpiece held on the porous ceramic rotary chuck table. A grinding method has also been proposed (for example, Patent Document 2). Ether.).

Furthermore, a rotating grindstone that holds the workpiece while being held in place by the grindstone feeding means, a workpiece support base that supports the workpiece, and a workpiece support base feed means that moves the workpiece support base in a direction parallel to the workpiece surface. A magnetic bearing device for controlling the position of the grindstone shaft of the rotating grindstone, and a grindstone feeding means and a workpiece support base feeding means using the axial direction control current and the radial direction control current of the magnetic bearing device. And a control means for controlling the feed of the workpiece support base based on the radial direction control current of the magnetic bearing device, and the rotating grindstone workpiece based on the axial direction control current of the magnetic bearing device. A surface grinding apparatus is also proposed in which a stop position in a direction perpendicular to the surface to be processed is controlled (see, for example, Patent Document 3).

Further, as a grinding wheel shaft bearing, a grinding wheel shaft that supports a rotor of a built-in motor is supported by a hydrostatic thrust bearing and a hydrostatic radial bearing, and the grinding wheel shaft is constituted by a heat pipe, and heat generation of the rotor is performed by a heat pipe. There is also known a grinding head that is supported by a hydrostatic bearing having a cooling structure that is transmitted in the longitudinal direction of the grinding wheel shaft and escapes from the hydrostatic bearing to the outside (see, for example, Patent Document 4).

  In order to support the wheel shaft radial direction force and thrust direction force, a one-piece hydrostatic bearing is provided, and the mounted wheel shaft is mounted with high rigidity without contact by water pressure, and the hydrostatic bearing The body has several channels that terminate at the spout, and between one or both of the spout and the mounted grindstone shaft and other elements adjacent in the plane A gap of different thickness is arranged, water flows through the jet nozzle, and the grindstone school to be mounted is supported by a water film, and the full force of this bearing is also applied to the grindstone shaft supported by the flange bolted to the grindstone. It has been proposed (see, for example, Patent Document 5).

  On the other hand, although not disclosed for use in a grinding apparatus, a composite (rotation / linear motion) actuator that rotates and linearly moves a rotatable / linearly movable tool spindle has also been proposed (for example, Patent Document 6, Patent) (Ref. Literature 7, Patent Literature 8, and Patent Literature 9).

  There is also known a test apparatus including a height position adjuster using a kinematic coupling in which a male member and a female member are coupled (see, for example, Patent Document 10 and Non-Patent Document 1).

Further, a porous chuck table made of a porous ceramic for work supported by a hydrostatic bearing has also been proposed (see, for example, Patent Document 11 and Patent Document 12).

Patent No. 3,472,784 JP 2005-22059 A JP 2005-262431 A Japanese Patent Laid-Open No. 11-235643 US Pat. No. 6,419,396 US Patent Application Publication No. 2007/0222401 JP 2006-220196 A JP 2004-364348 A JP 2006-220178 A US Pat. No. 6,104,202 Bal-tec, “Kinema coupling design for Z-axis”, {on-line}, pages 430-434, {searched May 30, 2005}, Internet <URL: http://www.precisionballs.com /kinematic_repeatability.html> US Patent Application Publication No. 2007/0286537 Japanese Patent Application Laid-Open No. 2000-240652

  Back surface grinding obtained using the grinding apparatus for tilting the grindstone shaft described in Patent Literature 1, Patent Literature 2 and Patent Literature 3 as long as the semiconductor substrate (workpiece) has a diameter of 200 mm or 300 mm and a thickness of 100 to 770 μm. The processed semiconductor substrate is a ground semiconductor substrate that has a thickness distribution (thickness fluctuation is around 1 μm) that can withstand the practical use of DRAM even if the central part is thin and the edge is thick. In a semiconductor substrate for DRAM having a thickness of 20 to 50 μm, the percentage of the thickness fluctuation with respect to the target thickness of 20 to 50 μm is as large as 2 to 5%, and the thickness distribution is more excellent (the thickness fluctuation is 0). It is desired to realize a highly rigid surface grinding apparatus that does not cause cracks or cracks in the semiconductor substrate during grinding.

  In addition, the semiconductor manufacturing industry dislikes that the substrate is soiled with oil during substrate processing, and the emergence of a hydrostatic bearing substrate surface grinding apparatus is desired. Furthermore, when the surface grinding head is not operating and long-term operation is stopped, there is a problem that algae are generated in the water passage of the hydrostatic bearing.

  An object of the present invention is to provide a surface grinding head system that supports a rotary / linearly movable grindstone shaft described in Patent Document 6, Patent Document 7, Patent Document 8, and Patent Document 9 with a hydrostatic bearing.

According to the first aspect of the present invention, there is provided a cup wheel type grindstone (14) supported by a lower end of a grindstone shaft (13) via a flange (14b ) , the grindstone shaft (13) being formed into a cylindrical shape with a cylindrical outer housing (15). A cylindrical housing material surrounded by a bearing housing (15 m) , a linear actuator (18) which thrust-bears the grindstone shaft (13) at the upper portion of the grindstone shaft and linearly moves up and down, and the grindstone shaft below the grindstone shaft consisting a rotary actuator for rotating (16) in parts rotation / linear actuator (16, 18), provided the wheel spindle (13) in the cylindrical bearing housing (15 m) the inner wall surrounding at lower portion of the wheel spindle water hydrostatic bearing for the radial bearing out was the water passage (15k) and the grinding wheel shaft (13), the cylindrical bearing housings provided in the outer side wall of the cylindrical outer housing (15) Grayed feed water inlet to inject water into (15 m) water passage provided in the inner wall (15e) (15a), vacuum decompression port by reducing the pressure in the water passage of the radical bearing (15k) to facilitate through water (15b) And a drain outlet (15d) for discharging the water in the water passage (15k) out of the cylindrical outer housing (15), and supplying pressurized air into the water passage (15k) to cause excess water to flow into the water passage. A compressed air supply port (15c) for sealing so as not to be supplied to (15k) , a cooling water passage ( 15h) for cooling the rotary actuator (16 ) on the inner wall of the cylindrical outer housing (15) , and the radial bearing portion The present invention provides a grinding head system (1) for a substrate comprising a grinding wheel shaft cooling mechanism provided with the cooling water passage (15e) for cooling.

In the invention of claim 2, the water supplied to the water passage (15k) provided in the inner wall of the cylindrical bearing housing (15m) is water in which 0.5 to 100 mg of a water-soluble algae is dissolved, or water-insoluble. The grinding head system (1) for a substrate according to claim 1, characterized in that the water is supplied from within a water tank containing an algaeproofing agent.

  An environmentally friendly grinding device can be provided by using a hydrostatic bearing as the grinding wheel shaft. When the surface grinding head system is shut down for a long period of time, the water passage port is first depressurized, and then the remaining water and water droplets are ground from the drain port by supplying compressed air into the water passage of the hydrostatic bearing. The discharge to the outside of the head system and the inside of the water passage can be dried, and the generation of water algae can be suppressed.

Furthermore, since the cutting of the cup wheel type grindstone into the substrate surface and the grinding of the substrate at the time of substrate grinding are performed by rotating and lowering the grindstone shaft by the rotary / linear motion actuator, the grinding time can be shortened. In other words, a grinding head structure in which a cup wheel type grindstone is supported by a grindstone shaft that is rotated and linearly moved by a composite actuator allows the grindstone shaft to move back and forth between 0 and 1.5 mm during surface grinding. Grinding time can be shortened by cutting into the substrate surface or retreating from the substrate surface and moving the surface grinding head system to the standby position by another grinding wheel shaft lifting mechanism.

  Hereinafter, the present invention will be described in more detail with reference to the drawings. FIG. 1 is a perspective view showing a main part of a surface grinding apparatus provided with a surface grinding head system according to the present invention. Two of the three fixed plate lifting mechanisms are shown with the ball screw housing material omitted. 2 is a front cross-sectional view of the surface grinding apparatus, FIG. 3 is a side cross-sectional view of the surface grinding apparatus, and FIG. 4 is a horizontal cross-sectional view of the surface grinding apparatus. . 5 is a plan view of the surface grinding apparatus, FIG. 6 is a front sectional view of the kinema coupling portion of the fixed plate elevating mechanism, FIG. 7 is a plan view of the kinema coupling portion of the fixed plate elevating mechanism, and FIG. 9 is a side view of the kinema coupling part, FIG. 9 is a front view of a height position measuring displacement sensor attached to the coupling part of the fixed plate lifting mechanism, FIG. 10 is a sectional view of the surface grinding head system, and FIG. It is sectional drawing of a chuck | rotary rotary table mechanism.

As shown in FIGS. 1, 2, and 3, the substrate surface grinding apparatus 100 is supported by a work chuck table mechanism 2 installed in the central circular mold cavity of the machine frame 9 and a grindstone shaft 13 that can rotate / linearly move. The surface grinding head system 1 in which the cup wheel type grindstone 14 is supported by a hydrostatic bearing and a magnetic bearing so as to be rotatable and linearly movable, the rotary / linear motion combined actuators 16 and 18 for rotating / linearly moving the grindstone shaft 13, An equilateral triangle or an isosceles triangle is formed with respect to the center point of the fixed plate 6 with the grinding head 1 fixed at the center of the lower surface and the lower surface of the fixed plate 6 with the grindstone shaft 13 provided in the vertical direction so that the grindstone shaft 13 is vertical. Three sets of kinema couplings that move the fixed plate up and down at three positions of the apex position and a fixed plate elevating mechanism 7 including a cylinder rod are configured as main assembly materials.

The work chuck rotary table mechanism 2 includes a porous ceramic rotary chuck table 21 supported by a hollow spindle 22, and the hollow spindle 22 is supported by a hydrostatic bearing, and the horizontal surface of the porous ceramic rotary chuck table 21. Is provided so as to be parallel to the bottom surface of the cup wheel type grindstone 14 supported by the grindstone shaft 13. The lower end of the hollow spindle 22 is connected to three supply pipes connected to a vacuum pump, a compressor, and a pure water supply pump (not shown) by a rotary joint 29. A switching valve is attached to the three supply pipes. Decompression during workpiece adsorption according to the substrate processing process, pressurization when the substrate is removed from the porous ceramic rotary chuck table, and cleaning of the porous ceramic rotary chuck table Switch when supplying pressurized water.

The machine frame 9 is made of marble, ceramic, black granite, resin concrete, cast steel, or the like.

Next, the structure of the surface grinding head system 1 will be described in detail with reference to FIGS. 2 and 3 and FIG. As shown in FIG. 10, in the grinding head system 1 that supports the cup wheel type grinding wheel 14 below the grinding wheel shaft 13, the bottom surface of the cutting edge 14 a arranged in parallel with the ring shape of the cup wheel type grinding wheel 14 is made of porous ceramic. It is set as a processing standby position of the grindstone shaft so as to be parallel to the surface of the rotary chuck table 21.

The grinding head system 1 is installed by suspending the grinding head so that the cup wheel type diamond grinding wheel 14 becomes the lower end from the center point of the bottom surface of the fixed plate 6 whose plane is an equilateral triangle.

The cutting edge 14a of the cup wheel type grinding wheel 14 is annularly arranged on the lower surface of the grinding wheel flange 14b, and the grinding liquid is supplied from the grinding liquid supply nozzles 14c and 14c to the annular concave groove provided on the upper surface of the grinding wheel flange 14b. . The rotational speed of the grindstone shaft can be up to 5,000 rpm, and a rotational speed of 1,000 to 2,500 rpm is used during substrate grinding.

The grindstone shaft 13 is surrounded by a cylindrical outer housing 15, and the lower portion of the grindstone shaft 13 is hydrostatically radial bearinged. A water passage 15e is provided in the inner wall of the cylindrical outer housing 15, and water is supplied to the water passage 15e from the water supply port 15a.

A water passage 15k of a radial bearing is provided in the inner wall of the cylindrical bearing housing (bush) 15m. Although not shown, water supplied by a pump from a water injection port provided in the outer wall of the cylindrical outer housing is not shown. Is supplied to a water passage provided in the inner wall of the cylindrical bearing housing. The cylindrical outer housing 15 further includes a vacuum pressure reducing port 15b for reducing the pressure in the water passage 15k to facilitate passage of water, a drain outlet 15d for discharging the water in the water passage 15k to the outside of the cylindrical outer housing, and the water. A pressurized air supply port 15c is provided for supplying pressurized air into the passage so as to prevent excess water from being supplied to the water passage. Water that has flowed through the water passage 15k between the cylindrical bearing housing 15m and the outer surface of the grindstone shaft 13 and bearing the grindstone shaft 13 is discharged from the drain outlet 15d. After the substrate grinding is completed, when the surface grinding head system is stopped for a long time, the water passage pressure reducing port 15b is first depressurized, and then the compressed air is supplied from the compressed air supply port 15c into the water passage 15k of the hydrostatic bearing. Water and water droplets to be discharged can be discharged out of the surface grinding head system 1 from the drain outlet 15d and the inside of the water passage can be dried, and generation of algae can be suppressed.

A built-in motor 16 that rotates the grindstone shaft 13 in the horizontal direction is installed at the center of the grindstone shaft 13, and the built-in motor 16 receives coolant supplied from a coolant introduction pipe 15 f provided in the cylindrical outer housing 15. It is guided to the discharge pipe 15g through the coolant flow path 15h provided on the inner wall of the cylindrical outer housing 15.

The radial bearing part chamber and the coolant chamber of the built-in motor 16 are partitioned by the lip seal 15j so that fluids (water and air) supplied to the respective chambers are not mixed.

A position sensor 85, which is a position detection element of the ball target 17 provided at the upper end of the grindstone shaft 13, is mounted above the grindstone shaft 13, and the grindstone shaft 13 to which the mover (permanent magnet) 18a is fixed is vertically moved. A coil 18b for moving about 0 to 1.5 mm is installed. The position sensor 85 reads the displacement of the ball target 17 and converts the measured value into an electrical signal and transmits it to a controller (not shown).

The built-in motor 16 can rotate the grindstone shaft 13, and the motor 18, which is a combination of the mover 18 a and the coil 18 b, can perform a thrust linear movement of 1.5 mm or less of the grindstone shaft 13. This is called a combined rotary / linear actuator.

  The material of the cylindrical outer housing 15 and the cylindrical bush 15m is preferably a ceramic such as silicon nitride, carbon nitride, silicon oxide, alumina, zirconia, etc., but a conventional stainless steel or chrome plated steel spindle surface is formed by ceramic chemical vapor deposition. It may be a coating having a thickness of ˜500 μm.

Next, the structure of the work chuck rotary table mechanism 2 will be described in detail with reference to FIGS. 2, 3 and 11. Workpiece chuck rotary table mechanism 2, hollow spindle 22, the water passage 23a to the inner wall, 25b is carbon nitride ceramic cylindrical bush 23 provided for journalled a porous ceramic rotary chuck table 21, the cylindrical S _{i C} Ceramic A water supply port 24a for supplying water and a vacuum pressure reducing port 24b for reducing the pressure in the water passages 24a and 25b so as to allow water to pass therethrough, and the water passages 23a and 25b. A drain outlet 24d for discharging the water inside the cylindrical outer housing, a pressurized air supply port 24c for sealing the excess water to be supplied to the water passage by supplying pressurized air into the water passage, and a hollow spindle 22 The surrounding cylindrical outer housing material 24 and the cooling water passage provided inside the cylindrical outer housing material are cooled. Water supply ports 24f and 26a to be supplied, drainage ports 24g and 26c for discharging water in the cooling water passage to the outside of the cylindrical outer housing material, a thrust bearing 25a provided above the hollow spindle 22 and a central portion of the hollow spindle 22 A rotary bearing 29 connected to the lower end of the hollow spindle 22, and a rotary joint 29 connected to the lower end of the hollow spindle 22. A vacuum pump that is a pressure reducing mechanism that depressurizes the fluid in the hollow spindle 22 pipe, a compressor that is a pressurized gas supply mechanism that pressurizes the hollow spindle pipe, and a water supply pump that supplies pure water into the hollow spindle 22 pipe Tube 22a, 22b.

  The water bearing the hollow spindle 22 through the water passages 23a and 25b between the inner wall of the cylindrical bearing housing 23 and the outer surface of the hollow spindle 22 is discharged from the drain outlet 24d. When the work chuck rotary table mechanism 2 is stopped for a long time after the substrate grinding, the water passage pressure reducing port 24b is first depressurized, and then the compressed air is supplied from the compressed air supply port 24c into the water passages 23a and 25b of the hydrostatic bearing. By doing so, remaining water and water droplets can be discharged out of the surface grinding head system 1 from the drain outlet 24d and the inside of the water passages 23a and 25b can be dried, and generation of algae can be suppressed.

  The material of the hollow spindle 22 and the cylindrical bush 23 is preferably a ceramic such as silicon nitride, carbon nitride, silicon oxide, alumina, zirconia, etc., but a conventional stainless steel or chrome plated steel spindle surface is 100 to 500 μm by ceramic chemical vapor deposition. A thick coating may be used.

Wherein the water passage of the thrust bearing 25a, the pure water from the pure water supply nozzle 25a ₁ provided eight supplied, draining from the discharge pipe 25a _2. Water is supplied to the water passage 23a of the radial bearing 25b from the water supply port 24c and drained from the drain outlet 24d. The cooling water of the built-in motor 27 is supplied from the water supply port 26a and drained from the discharge port 26b. Cooling water for cooling the built-in motor 27 is supplied from the water supply port 24a and discharged from the drain port 26b.

The workpiece (substrate) is placed on the porous ceramic rotary chuck table 21, the vacuum pump is operated to fix the workpiece on the porous ceramic table 21, and the built-in motor 27 then holds the hollow spindle 22. Rotate horizontally. The rotation speed of the hollow spindle 22 can be up to 500 rpm, and is used at 50 to 200 rpm during substrate grinding.

  As shown in FIGS. 1, 2, and 3, the fixed plate lifting mechanism 7 has a cross section having a hole through which a ball screw 72 passes in the center fixed to the upper surface of the base 9 a of the machine frame 9 of the work chuck rotary table mechanism 2. A V-shaped coupling female member 73, a coupling male member 74 having a V-shaped cross-sectional shape that has a hole through which a ball screw 72 penetrates in the center and fits into the inner surface of the V concave portion of the coupling female member 73, A ball screw 72 installed through the through hole of the coupling female member and the through hole of the coupling female member on the vertical line and the lower end of the ball screw are rotated by a fixture 79a at the bottom of the machine base 9a of the work chuck rotary table mechanism 2. The upper end of the ball screw can be rotated by a fixed fitting plate 79b on the lower surface of the fixed plate 6 of the grinding head 1. Fixed, ball screw drive motor 71 and the encoder 76 and a ball screw threadably united 77 is attached to the upper end of the ball screw 72. A wedge 83 attached to the tip of a ball screw 81 is provided in the space 70 formed by the V recess of the coupling female member 73 and the bottom surface of the coupling male member 74 by driving the micro servo motor 82. 70 is provided so as to be able to move forward and backward.

A wedge attached to the tip of a ball screw 81 that can be moved forward and backward by driving the micro servo motor 82 in a space 70 formed by a V recess 73a of the coupling female member 73 and a bottom surface of the coupling male member 74. 83, and then the ball screw 72 is driven to depress the coupling male member 74 and bring the bottom surface of the male member into contact with the top surface of the wedge 83, thereby increasing the height between the bottom surface of the fixing plate 6 and the surface of the rotary chuck table 21 made of porous ceramic. The height is slightly higher. On the other hand, when the wedge 83 is retracted from the space 70 and then the ball screw 72 is driven to push down the coupling male member 74 to bring the male member bottom surface into contact with the top surface of the wedge 83, the bottom surface of the fixing plate 6 and the porous ceramic rotary chuck The height between the tables 21 is slightly reduced. The height between the bottom surface of the fixed plate 6 and the horizontal surface of the porous ceramic rotary chuck table 21 is determined by the contact between the top surface of the wedge 83 and the bottom surface of the coupling male member 74.

  3 and FIG. 4, in the vicinity of the porous ceramic rotary chuck table 21 of the work chuck rotary table mechanism 2, probe pins are respectively brought into contact with the workpiece surface and the porous ceramic rotary chuck table 21 surface. A two-point process indicator 91 for measuring the thickness of the substrate is provided. The thickness of the substrate is used to determine an inclination angle of the grindstone shaft with respect to the substrate surface when the substrate is ground.

The ratio of the diameter _{r g} of the annular grinding blade of the cup wheel type grinding wheel 14 to the diameter _{r c} of the porous ceramic rotary chuck table 21 _(r g / r _c) is 1.01 to 1.25 times are preferred. The cup wheel type grindstone 14 is supported by the grindstone shaft 13 so that the annular grindstone blade of the cup wheel type grindstone 14 passes through the center point of the substrate.

Further, three linear sensors 84 for measuring the height position of the bottom surface of the fixed plate are provided on the side of the coupling female member 73 of the fixed plate lifting mechanism 7. Before grinding, the height of the three points between the surface of the porous ceramic rotary chuck table 21 and the bottom surface of the fixed plate, the kinematic coupling portion cavity 70 entry and retract distances of the three wedges 83, and the porous ceramic of the grindstone shaft 13 Correlation data of the tilt angle with respect to the surface of the made rotary chuck table 21 is preliminarily compiled in a table and stored in the memory of the numerical control device, thereby changing the tilt angle of the grindstone shaft 13 according to the thickness of the ground substrate. A machining software program can be designed. The grinding wheel shaft tilt angle changing software program is a grinding wheel shaft tilt angle software program that adopts a system in which the ball screw 72 (cylinder rod) of the fixed plate lifting mechanism 7 supports the bottom surface of the fixed plate 6 at the three vertex positions of an equilateral triangle. Easy design.

The method of grinding the substrate at three different contact point positions by changing the angle of the grindstone shaft 13 with respect to the substrate surface during the grinding of the substrate is even better than the method of grinding the substrate at one contact point position. A ground substrate having high flatness is provided.

In the coupling parts 73 and 74 of the fixed plate elevating mechanism 7 shown in FIGS. 6, 7, and 8 except for the ball screw 72, the female member 73 is on the surface of the machine base 9 a of the work chuck rotary table mechanism 2. It is fixed to. The female member 73 has a V-shaped cross section, and the bottom 73a is inclined. The female member 73 has a hole through which the ball screw 72 passes in the center.

The male member 74 includes a plate 74a having a substantially V-shaped cross section that forms two bottom portions, a plate 74b having a small width provided above the plate 74, and a side wall plate 74c that fixes the two plates. And the bottom of the plate 74a having a substantially V-shaped cross section is also inclined. A space 70 is formed by the bottom surface of the plate 74 a having a substantially V-shaped cross section and the V-shaped recess of the female member 73.

The ball screw 72 is inserted into the through hole of the female member 73 and the through hole of the male member 74 in the vertical direction.

In the space 70 formed by the female member 73 and the male member 74, a wedge 83 attached to the tip of the ball screw 81 is provided so as to move forward and backward by driving the micro servo motor 82. A ball screw 81 for moving the wedge 83 back and forth in the space 70 is also installed with an inclination of 4 to 7 degrees with respect to the upper surface of the machine frame base 9a, similar to the inclination of the bottom of the female member 73.

  On the opposite side where the micro servo motor 82 is installed, three linear sensors 84 are installed as shown in FIGS. 4, 6 and 9, and the linear sensor 84 is composed of a bottom surface of the fixing plate 6 and a porous ceramic rotary. The vertical distance between the surfaces of the chuck table 21 is measured.

  Further, as shown in FIG. 8, a height position measuring sensor 86 having a pair of measuring probes is attached to the side wall plate 74c of the male member 74 constituting the kinema coupling in order to measure the height of the void 70. It has been.

  The fixed plate elevating mechanism 7 may be a height adjusting device including a kinema coupling and a cylinder rod that can move the height position of the fixed plate 6. For example, instead of the servo motor drive ball screw 72 described above, a fixed plate lifting mechanism using a cylinder rod that can be moved up and down by a pneumatic or hydraulic cylinder can be used. Further, the ball screw drive motor position of the above-described fixed plate lifting mechanism 7 may be installed upside down on the bottom side of the machine base 9a. Further, a structure in which the structure of the female member 73, male member 74, and wedge 83 of the kinema coupling is changed to a known kinema coupling structure may be used.

  A process of flattening and grinding a substrate using the substrate surface grinding apparatus 100 shown in FIG. 1 will be described below.

1) The substrate is placed on the porous ceramic rotary chuck table 21 using a transfer robot or a transfer pad, and then the vacuum pump is operated to depressurize the decompression chamber 21a on the bottom surface of the porous ceramic rotary chuck table. It is fixed on a rotary chuck table 21 made of porous ceramic.

  2) The built-in motor 27 is driven to rotate the hollow spindle 22.

3) After driving the three ball screws 72 of the fixed plate lifting mechanism 7 of the fixed plate 6 that hangs down and fixes the grinding head 1 in the standby position to raise the fixed plate 6, the coupling of the fixed plate lifting mechanism 7 While a wedge 83 attached to the tip of a ball screw 81 that can be moved forward and backward by driving by one of the micro servo motors 82 is inserted into a space 70 formed by the female member 73 and the coupling male member 74, another micro The wedge 83 attached to the tip of the ball screw 81 which can be moved forward and backward by driving with two servo motors 82 is retracted, and then the ball screw 72 is driven to push down the coupling male member 74 so that the bottom surface of the male member is wedge 83. The height between the bottom surface of the fixed plate 6 and the surface of the porous ceramic rotary chuck table 21 is set in contact with the upper surface.

4) While the grindstone shaft 13 is rotated by the built-in motor 16, the ball screw 72 of the fixed plate elevating mechanism 7 is lowered and the cup wheel type diamond grinding grindstone 14 is rubbed against the rotating substrate surface to start grinding cutting of the substrate. To do. At this time, the grinding liquid is supplied from the supply nozzle 14 c into the upper groove of the flange 14 b of the cup wheel type diamond grinding wheel 14, and the grinding liquid is supplied to the substrate surface via the through holes provided obliquely to the flange wall. The wheel blade 14a of the wheel-type diamond grinding wheel 14 and the substrate are cooled. The grinding wheel shaft lower feed for cutting the substrate is performed by grinding wheel shaft feeding by a combined rotary / linear motion actuator.

  5) During grinding, the thickness of the substrate is measured by the two-point process indicator 91, and the fixed plate 6 is instructed by the grinding wheel shaft tilting program in which the tilting angle of the grinding wheel shaft 13 with respect to the substrate surface is determined based on the thickness value. In order to make it the height position, the fixing plate 6 is raised by raising the ball screw 72 of the fixing plate raising / lowering mechanism 7 described above to slightly increase the height of the space 70 of the female member 73 and the male member 74, Attach a wedge 83 attached to the tip of a ball screw 81 that can be moved forward and backward by driving with two micro servo motors 82, and attach it to the tip of a ball screw 81 that can be moved forward and backward by driving by one of the other micro servo motors 82. The wedge 83 is retracted, and then the ball screw 72 is driven to push down the coupling male member 74 so that the bottom surface of the male member is brought to the upper surface of the wedge 83. To contact perform height setting between the fixed plate 6 bottom and porous ceramic rotary chuck table 21 surface.

6) The grindstone shaft 13 whose angle has been adjusted is lowered by lowering the ball screw 72 of the fixed plate elevating mechanism 7 and brought into contact with the substrate surface of the grindstone blade 14a of the cup wheel type diamond grinding grindstone 14, and the substrate surface by the grindstone blade 14a is contacted. Resume rubbing. The grinding wheel shaft lower feed for cutting the substrate is performed by grinding wheel shaft feeding by a combined rotary / linear motion actuator.

7) The substrate thickness measurement and the grindstone axis tilt angle adjustment in the above 5) step, and the substrate rubbing in the 6) step are repeated. When the thickness of the substrate is close to the desired final thickness, or when the final thickness is reached, the inclination angle of the grindstone shaft 13 with respect to the substrate surface is 0 degree (the bottom surface of the fixed plate 6 or an annular grindstone blade 14a of a cup wheel type diamond grinding grindstone). The grinding wheel shaft inclination angle is decreased for a while so that the bottom surface of the group is parallel to the horizontal surface of the substrate or the surface of the machine base 9a.

8) After completion of the substrate grinding process, the ball screw 72 of the fixed plate elevating mechanism 7 is raised to retract the grinding head 1 upward and return to the standby position away from the grinding substrate. At the grinding head standby position, the distance to the bottom surface of the fixed plate 6 is measured using the linear sensor 84, and it is confirmed whether the inclination angle of the grindstone shaft 13 with respect to the substrate surface is 0 degree. When it is not 0 degree, the raising / lowering of the three ball screws 72 of the fixed plate raising / lowering mechanism 7 is adjusted, and the inclination angle with respect to the substrate surface of the grindstone shaft 13 is adjusted to 0 degree.

9) After the rotation of the porous ceramic rotary chuck table 21 is stopped, the vacuum pump is stopped, and then pressurized water is supplied to the bottom surface of the porous ceramic rotary chuck table 21 to provide a porous ceramic rotary chuck table for the ground substrate. 21 The substrate can be easily peeled from the surface.

10) The ground substrate is sucked by the transport robot or the transport pad, and the ground substrate is transferred from the surface of the porous ceramic rotary chuck table 21 to the next processing step.

11) After the surface of the porous ceramic rotary chuck table 21 is cleaned by a porous ceramic rotary chuck table cleaning device (not shown), pressurized water is jetted from the bottom surface 21a of the porous ceramic rotary chuck table for 0.1 to 0.5 seconds ( The ceramic ceramic rotary chuck table is cleaned.

The water supplied to the water passage 15k provided on the inner wall of the cylindrical bearing housing (bushing) 15m and the water passages 23a and 25b of the cylindrical bearing housing 23 dissolves 0.5 to 100 mg of a water-soluble algae. Water or water supplied from the inside of a water tank containing a water-insoluble algae suppressant is preferable. Examples of the water-soluble algae preventive agent include glycerylated chitosan salt and sulfamic acid obtained by reacting an addition reaction product of isouron-D-glucose and oxirane methanol with an organic acid such as lactic acid, malic acid, citric acid, or pyrrolidocarboxylic acid. And a mixture of sodium hypochlorite and the like, and as the water-insoluble algae preventive agent, a copper fiber filter, zinc oxide whisker, silver ion-containing zeolite and the like can be used.

  The surface grinding apparatus 100 including the substrate surface grinding head system 1 according to the present invention has a hydrostatic bearing on the grinding wheel shaft, and is environmentally friendly.

It is a perspective view which shows the principal part of the surface grinding apparatus for substrates. It is sectional drawing of a surface grinding apparatus. It is a top view of a surface grinding apparatus. It is horizontal direction sectional drawing of a surface grinding apparatus. It is a top view of a surface grinding apparatus. It is front sectional drawing of the kinema coupling part of a fixed plate raising / lowering mechanism. It is a top view of the kinema coupling part of a fixed plate raising / lowering mechanism. It is a side view of the kinema coupling part of a fixed plate raising / lowering mechanism. It is a front view of the height position measurement displacement sensor attached to the kinema coupling part of the fixed plate lifting mechanism. It is sectional drawing of a grinding head system. It is sectional drawing of a work chuck rotary table mechanism.

Explanation of symbols

DESCRIPTION OF SYMBOLS 100 Surface grinding machine 1 Surface grinding head system 13 Grinding wheel axis 14 Cup wheel type grinding wheel 14c Grinding fluid supply nozzle 15 Cylindrical housing 16, 18 Rotary / linear motion combined actuator 2 Work chuck rotary table mechanism 21 Porous ceramic rotary chuck table 22 Hollow Spindle 23 Cylindrical bush made of carbon nitride ceramic 24 Cylindrical housing member 25a Thrust bearing 25b Radial bearing 23a, 25a ₁ Water passage 27 Built-in motor 28 Encoder 29 Rotary joint 6 Grinding head fixing plate 7 Fixed plate lifting mechanism 70 Empty space 71 Ball screw Drive motor 72 Ball screw 73 Coupling female member 74 Coupling male member 76 Encoder 79a Fixing tool 79b Fixed fitting plate 81 Ball screw 82 Micro Servo Motor 83 Wedge 84 Linear Sensor 85 Height Position Measurement Sensor 9 Machine Frame 9a Machine Frame Base 91 Two-point Process Indicator

Claims (2)

A cup wheel type grindstone (14) supported by a lower end of a grindstone shaft (13) via a flange (14b), and the grindstone shaft (13) is formed by a cylindrical outer housing (15) and a cylindrical bearing housing (15m) . A surrounding cylindrical housing member, a linear actuator (18) for thrust-bearing the grindstone shaft (13) at the upper portion of the grindstone shaft and moving it vertically up and down, and a rotary actuator for rotating the grindstone shaft at the lower portion of the grindstone shaft ( 16) and consisting of the rotation / linear actuator (16, 18), said wheel spindle (13) the cylindrical bearing housing surrounded by the lower part of the wheel spindle (15 m) water passage provided in the inner wall (15k) and the grinding wheel axis (13) and out the radial bearing water hydrostatic bearing, the cylindrical bearing housing (15 m) the inner wall provided outside wall of said cylindrical outer housing (15) Feeding Mizuguchi the provided water passage (15e) for injecting water (15a), said radicals and vacuum the water passage (15k) in the bearing vacuum vacuum port to facilitate through water (15b) and said water passage (15k excess water is not supplied to the water channel (15k) a) in water cylindrical outer housing (15) by supplying pressurized air drain is discharged to the outside抜口(15d) to the water passage (15k) in A compressed air supply port (15c) for sealing, a cooling water passage ( 15h) for cooling the rotary actuator (16 ) on the inner wall of the cylindrical outer housing (15) , and the cooling water passage for cooling the radial bearing portion A grinding head system (1) for a substrate comprising a grinding wheel shaft cooling mechanism provided with (15e ) . Water supplied to a water passage (15k) provided in the inner wall of the cylindrical bearing housing (15m) is water in which 0.5 to 100 mg of water-soluble algae is dissolved, or a water tank containing water-insoluble algae The grinding head system (1) for a substrate according to claim 1, characterized in that the water is supplied from within.

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